Dr James Hansen (top US climate scientist; former Director, NASA Goddard Institute for Space Studies; member of the prestigious US National Academy of Sciences; 2007 Award for Scientific Freedom and Responsibility of the prestigious American Association for the Advancement of Science; Adjunct Professor, Columbia University, New York, USA) (2009): “Today, following global cooling over millions of years, the methane hydrate reservoir is fully charged. The size of the hydrate reservoir is difficult to determine from spotty field data. However , methane hydrate models that are consistent with the limited data suggest a total inventory of about 5,000 Gigatons of carbon in the form of methane ice and methane bubbles. Thus, unfortunately, not only is the methane gun now fully loaded, but it also ha s a charge larger than the one that existed prior to the PETM blast [Paleo-Eocene Thermal Maximum mass extinction event 55 million years ago]” (James Hansen “Storms of My Grandchildren”, Bloomsbury, 2009,page163).
[Editor note: 5000 Gigatons (Gt) carbon (C) corresponds to 5,000 Gt C x 16 Gt CH4 / 12 Gt C = 6,667 Gt CH4. The Global Warming Potential (GWP) of CH4 is 21 times that of CO2 on a 100 year time frame but is 105 times greater than that of CO2 on a 20 year time frame and taking atmospheric aerosol impacts into account. Accordingly, the 6,667 Gt C as CH4 corresponds to 6,667 x 105 Gt CO2-equivalent (CO2-e) = 700,000 Gt CO2-e. The German WBGU (2009) and the Australian Climate Commission (2013) have estimated that no more than a Terminal Carbon Pollution Budget of 600 billion tonnes of CO2 (Gt CO2) can be emitted between 2010 and zero emissions in 2050 if the world is to have a 75% chance of avoiding a catastrophic 2C temperature rise. The 50 Gt (billion tonnes) CH4 in the East Siberian Arctic Shelf that is predicted to be released in coming decades is thus equivalent to 50 Gt CH4 x 105 Gt CO2-equivalent/Gt CH4 = 5,250 Gt CO2-e or about nine (9) times more than the world’s Terminal Carbon Pollution Budget of 600 Gt CO2. The 700,000 Gt CO2-e of methane stored in the “methane gun” is thus over 1,000 times more than the world’s Terminal Carbon Pollution Budget of 600 Gt CO2 (see “Methane Bomb Threat”: https://sites.google.com/site/methanebombthreat/ )].